After the formation of the Clans in the Pentagon Worlds, the ship became part of Clan Mongoose's WarShip fleet. Renamed the Quicksilver Mongoose, it was rebuilt with Clan technology and made into the flagship of their fleet. In the Clan's Trial of Absorption in 2868, the ship's most noted action was against the Clan Smoke Jaguar fleet around Circe. The Quicksilver Mongoose was able to conduct a crippling attack against the Jaguar Flagship, the McKenna-class battleship CSJ Obsidian. This would be its finest moment, as the struggle above Circe seemed to finally have turned in favor of Clan Mongoose, allowing the cruiser-based Mongoose fleet to regroup and press the attack again. However, a Jaguar destroyer, the Lola III-class CSJ Storm Cat, managed to cripple the Quicksilver Mongoose shortly after its successful attack. Battered and leaking atmosphere, the crew watched as the rest of the Mongoose fleet struggled to maintain the momentum the Quicksilver Mongoose had given them. In the end, the remaining four WarShips of the Mongoose fleet surrendered to the Smoke Jaguars.[1]

After the Smoke Jaguar's absorption of the Mongooses, the ship was mothballed in the Strana Mechty system by the Jaguars. Prior to losing contact with Inner Sphere, the ship was known to still be there.[2]

Clan Mongoose had refitted her with Clan technologies, increasing the ancient design's firepower. The designers began by doubling the ship's front arc capital weaponry with eight Heavy & four Medium Naval PPCs on its bow. On its sides, the ship's Class 45 Naval Lasers were augemented by pair of Light Naval PPCs per arc, while adding a few more NLs per arc. The ship's aft remained the same with its pair of Medium Naval PPCs.

The designers added standard weaponry to increase the ship's self-defense abilities against smaller Aerospace fighter attack. Adding sets of Large & Small Pulse Lasers in all its arcs.